Heat pump compressors are currently mounted in hermatically sealed vessels with low side (suction) vapor delivered to the vessel where it serves as the coolant for the motor and oil. The vessel is installed outdoors and is not insulated. In the heating mode, heat losses generated in the vessel are lost to the atmosphere by convection. If the vessel is installed indoors to conserve this heat, the sensible cooling capacity is reduced in the summer cooling mode by the heat which escapes into the space to be cooled. It would be desirable to use such heat losses in the winter to warm an interior space and to be able to vent the heat losses to atmosphere during the summer. A need has, therefore, arisen to provide apparatus and a method to accomplish this to render the heat pump more efficient all year around.